This study examined the relationship between bisexual identity congruence, internalized biphobia and infidelity among women who are attracted to men and women. Bisexual identity congruence was measured by an adapted Klein Sexual Orientation Grid, internalized biphobia was measured by an adapted version of the Lesbian Internalized Homophobia Scale and infidelity was measured by a questionnaire created by the authors measuring sexual and emotional infidelity in relationships with men and with women. Results showed a significant relationship between bisexual identity congruence and internalized biphobia, and a significant difference between faithful and unfaithful women in terms of their levels of internalized biphobia.